单项选择题
A.0.1dBB.0.2dBC.0.3dBD.0.5dB
A.小于0.8μmB.0.8~1.2μmC.1.2~1.65μmD.大于1.65μm
A.纤芯直径B.纤芯半径C.纤芯折射率D.包层折射率